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Type: Posts; User: zydgyy

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1. ## Thread: how to calculate coordinates of rect by image dimension

by zydgyy
Replies
8
Views
1,925

### Yes,i know this,but how to make the image not...

Yes,i know this,but how to make the image not magnify and shrink
2. ## Thread: how to calculate coordinates of rect by image dimension

by zydgyy
Replies
8
Views
1,925

### Is there anybody can help me out?

Is there anybody can help me out?
3. ## Thread: how to calculate coordinates of rect by image dimension

by zydgyy
Replies
8
Views
1,925

### Can this method achieve?

Can this method achieve?
4. ## Thread: how to calculate coordinates of rect by image dimension

by zydgyy
Replies
8
Views
1,925

### No,i want the image cover my rect,and it's not...

No,i want the image cover my rect,and it's not distorted
5. ## Thread: how to calculate coordinates of rect by image dimension

by zydgyy
Replies
8
Views
1,925

### how to calculate coordinates of rect by image dimension

if i have an image 123x256 pixels
if i draw a rect that have the same size as this image,how can i calculate the coordinates of vertices of this rect by modelview,projectio,viewport and image...
6. ## Thread: what is alpha mask,is this in opengl

by zydgyy
Replies
1
Views
994

### what is alpha mask,is this in opengl

Can i use it make my rectangle round corner??
7. ## Thread: about up vector of camera

by zydgyy
Replies
1
Views
1,138

### about up vector of camera

about the function glLooAt(x,x,x, x,x,x, upx,upy,upz);
if i use it to set my camera,and up vecotr is (0,-1,0),so
what are the pitch,yaw,roll components???
8. ## Thread: how to get the 4 corners object coordinates of my screen

by zydgyy
Replies
1
Views
676

### how to get the 4 corners object coordinates of my screen

#include <stdio.h>
#ifdef __cplusplus
extern "C"
#endif
FILE _iob[3] = {__iob_func()[0], __iob_func()[1], __iob_func()[2]};
#include "shared/gltools.h" // OpenGL toolkit
#include <math.h>...
9. ## Thread: about gluLookAt function and how to rotate the camera

by zydgyy
Replies
5
Views
3,354

### OK,addtional question: this is my code: void...

this is my code:
void RenderScene(void)
{
// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Save the matrix state...
10. ## Thread: about gluLookAt function and how to rotate the camera

by zydgyy
Replies
5
Views
3,354

### about gluLookAt function and how to rotate the camera

Sorry,as i am a newbie to opengl,
if i use the gluLookAt(x,x,x,y,y,y,0,-1,0)
so ,i know the(0,-1,0) is th camera up-vector,but if i use the parameter set the camera in my 3ds max,so how do i roate...
11. ## Thread: gluLookAt(675.0, 345.0, -1287.557, 675.0, 345.0, 1, 0, -1, 0) and pitch,yaw,roll

by zydgyy
Replies
1
Views
525

### gluLookAt(675.0, 345.0, -1287.557, 675.0, 345.0, 1, 0, -1, 0) and pitch,yaw,roll

how can i get these three componets through this function call?
12. ## Thread: any suggestions???

by zydgyy
Replies
1
Views
645

### any suggestions???

Hi,guys!
is there somebody knows about the CEGUI,i tracked the source code,and found this framework use the below model-view matrix through glMatrixMode(GL_MODELVIEW);glLoadMatrixf(mat);and the mat...
13. ## Thread: about matrix usage in opengl

by zydgyy
Replies
2
Views
523

### about matrix usage in opengl

Here is my test,

and i change the code link this,

first i construct two matrix,use glMulMatrix to multiply the first,and then use it again to multiply the sencod.
14. ## Thread: about perspective projection matrix

by zydgyy
Replies
3
Views
1,433

### Yes,there is no fovy,but i can't understand the...

Yes,there is no fovy,but i can't understand the matrix usage?!
15. ## Thread: about perspective projection matrix

by zydgyy
Replies
3
Views
1,433

### about perspective projection matrix

here is from "http://www.opengl.org/sdk/docs/man/"

and here is my matrix in question:

So what does this matrix represent,orth,perspertive?

by zydgyy
Replies
1
Views
401

### about texture map

Can i specify texture map for diffuse and ambient respectively,just like 3ds max mutilple map channels!???
17. ## Thread: this confuse me

by zydgyy
Replies
1
Views
329

### this confuse me

Hi,guys:
about winding in opengl,i have a little confusion!

So,the first winding is the same as the second winding???
Sorry,new to opengl and 3d graphics!
18. ## Thread: how to get the vertices coordinates

by zydgyy
Replies
3
Views
1,295

### how to get the vertices coordinates

Hi,i am new to computer graphic
I want to know this:
If i have view matrix and projection matrix,and can i know the vertex coordinates of say,at the center of my viewport or the top-left of my...
19. ## Thread: tow basic questions

by zydgyy
Replies
3
Views
477

### Re: tow basic questions

1)it just coufuse me,if i use a normal to specify which way is out and it is inverted as the wound-order,what hanppend?
20. ## Thread: tow basic questions

by zydgyy
Replies
3
Views
477

### tow basic questions

Hi,
1)i read about there are two methods to determine which face of a polygon is up,by specifying a normal verctor and by specifying wounding orientation of vertices(clock-wise or counter-clock...
21. ## Thread: camera,view matrix,scnen graph

by zydgyy
Replies
1
Views
741

### camera,view matrix,scnen graph

Hi,i known about there is a camera object in some enginee and it has own poisition and orientation,and it can be attached to a node of scene graph which can has own position and orientation as...
22. ## Thread: how to set a mesh self-illumination

by zydgyy
Replies
1
Views
666

### how to set a mesh self-illumination

Can i a set emission property of meatreial of a mesh to achieve self-illumination like this mesh just be a light!!!?!

by zydgyy
Replies
3
Views
939

### Re: about edge flag

Otherwise,how does opengl implement backface culling?specify the vertices wound?colockwise,counter-colockwise??I read about a way calculate the degree between nromal of face and view...

by zydgyy
Replies
3
Views
939

### about edge flag

If i specify the edge flags of a mesh,would it get a more efficiency to GPU or just visibility-well?
25. ## Thread: given view matrix,can i retrieve these infos?

by zydgyy
Replies
1
Views
886

### given view matrix,can i retrieve these infos?

Can i retrieve position,orientaion,direction.Sorry,execute my poor math!
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